Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial syste...Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial system. Limitation in available flow chambers with a constant WSSG in the testing region makes it difficult to quantify cellular responses to WSSG. The current study proposes and characterizes a type of converging parallel plate flow chamber (PPFC) featuring a constant gradient of WSS. A simple formula was derived for the curvature of side walls, which relates WSSG to flow rate (Q), height of the PPFC (h), length of the convergent section (L), its widths at the entrance (w0) and exit (w1). CFD simulation of flow in the chamber is carried out. Constant WSSG is observed in most regions of the top and bottom plates except those in close proximity of side walls. A change in Q or h induces equally proportional changes in WSS and WSSG whereas an alteration in the ratio between w0 and w1 results in a more significant change in WSSG than that in WSS. The current design makes possible an easy quantification of WSSG on endothelial cells in the flow chamber.展开更多
The interaction mechanism between the plasma and liquid is a key problem for the electrothermal chemical launch technology. To investigate this problem, a simulated experiment for the expansion process of a plasma jet...The interaction mechanism between the plasma and liquid is a key problem for the electrothermal chemical launch technology. To investigate this problem, a simulated experiment for the expansion process of a plasma jet in the working fluid is carried on. Based on this experiment, a two-dimensional axisymmetric unsteady theoretical model is established to reveal the plasma-liquid interaction flow field pattern. The results show that a typical Taylor cavity forms as the plasma jet expands in liquid. The induction effect of the stepped-wall structure enhances the radial expansion of the plasma jet. An arc-shaped pressure wave is generated at the front of the plasma jet and then evolves into the plane wave. A high-pressure area forms at the head of the plasma jet and then moves downstream. There is a strong plasma-liquid turbulent mixing at the interface, especially near the steps and the nozzle exit area.展开更多
With high rock slope in shiplock area, thin reinforced concrete lining walls are constructed for the shiplock system. The construction technology involves much complicated structures in formwork, frequent interference...With high rock slope in shiplock area, thin reinforced concrete lining walls are constructed for the shiplock system. The construction technology involves much complicated structures in formwork, frequent interference due to crossover working procedures, tight time schedule, high quality of reinforced concrete and showcase appearance requirements, hidden troubles affecting construction safety. With above-mentioned factors in consideration, a single-side-separated sliding formwork technology advanced from past sliding formwork experiences has been developed and applied successfully. This new technology is beneficial in quick and safe operation, capable to assure best quality and appearance of shiplock concrete works, and has filled up the gap in terms of construction sliding formwork in our country.展开更多
文摘Many in vitro studies focus on effects of wall shear stress (WSS) and wall shear stress gradient (WSSG) on endothelial cells, which are linked to the initiation and progression of atherosclerosis in the arterial system. Limitation in available flow chambers with a constant WSSG in the testing region makes it difficult to quantify cellular responses to WSSG. The current study proposes and characterizes a type of converging parallel plate flow chamber (PPFC) featuring a constant gradient of WSS. A simple formula was derived for the curvature of side walls, which relates WSSG to flow rate (Q), height of the PPFC (h), length of the convergent section (L), its widths at the entrance (w0) and exit (w1). CFD simulation of flow in the chamber is carried out. Constant WSSG is observed in most regions of the top and bottom plates except those in close proximity of side walls. A change in Q or h induces equally proportional changes in WSS and WSSG whereas an alteration in the ratio between w0 and w1 results in a more significant change in WSSG than that in WSS. The current design makes possible an easy quantification of WSSG on endothelial cells in the flow chamber.
文摘The interaction mechanism between the plasma and liquid is a key problem for the electrothermal chemical launch technology. To investigate this problem, a simulated experiment for the expansion process of a plasma jet in the working fluid is carried on. Based on this experiment, a two-dimensional axisymmetric unsteady theoretical model is established to reveal the plasma-liquid interaction flow field pattern. The results show that a typical Taylor cavity forms as the plasma jet expands in liquid. The induction effect of the stepped-wall structure enhances the radial expansion of the plasma jet. An arc-shaped pressure wave is generated at the front of the plasma jet and then evolves into the plane wave. A high-pressure area forms at the head of the plasma jet and then moves downstream. There is a strong plasma-liquid turbulent mixing at the interface, especially near the steps and the nozzle exit area.
文摘With high rock slope in shiplock area, thin reinforced concrete lining walls are constructed for the shiplock system. The construction technology involves much complicated structures in formwork, frequent interference due to crossover working procedures, tight time schedule, high quality of reinforced concrete and showcase appearance requirements, hidden troubles affecting construction safety. With above-mentioned factors in consideration, a single-side-separated sliding formwork technology advanced from past sliding formwork experiences has been developed and applied successfully. This new technology is beneficial in quick and safe operation, capable to assure best quality and appearance of shiplock concrete works, and has filled up the gap in terms of construction sliding formwork in our country.
